Combination accumulator, heat exchanger, and metering device for refrigerating systems



Nov. 21, 1950 M. T. CAHENZLI, JR. ETAL 2,530,648

COMBINATIQN'ACCUMULATOR, HEA'I EXCHANGER, AND METERING DEVICE FORREFRIGERATING SYSTEMS Filed Sept. 26, 1946 Patented Nov. 21, 1950COMBINATION ACCUMULATOR, HEAT EX- CHANGER, AND METERING DEVICE FORREFRIGERATING SYSTEMS Martin T. Cahenzli, Jr., Chicago, 111., and GlennMuffl'y, Springfield, Ohio, assignors to The Harry Alter Company,Chicago, 111., a corporation of Illinois Application September 26, 1946,Serial No. 699,490

9 Claims.

1 s This invention relates to improvements in a combination unit forrefrigerating systems, and more particularly to a unit readily installedwith a minimum of labor in the suction side of a refrigerating system,the unit containing means to function as a metering device for fluidpassing through the high pressure side of the system, and

as a. heat exchanger, or in another form as a combination accumulator,heat exchanger, and metering device, although the invention may haveother uses and purposes as will be apparent to 1 one skilled in the art.

It is now'accepted in the trade that a highly satisfactory way ofcontrolling the flow of refrigerant from theconde'nser to the evaporatorin a refrigerating system is by means of a metering tube, sometimesreferred to as a capillary tube. Such a tube restricts the flow ofrefrigerant by virtue of its small internal diameter, by virtue of theshaping of the tube, or by virtue of a combination of both. It is alsodesirable to effect a heat exchange in the system so that the liquidrefrigerant passing to the evaporator may be initially chilled to aconsiderable extent before it reaches the evaporator thus lessening theload on the compressor and cutting down the operation of themechanically moving parts of the system in the event it is an automaticstop and start system; This is most frequently accom- .,plished byassociating a portion of the pressure lineintimately with'the suctionline so that the refrigerant traveling through the suction line becomeswarmer'by the extraction of heat from the refrigerant in the pressureline.

In the past, various arrangements have been provided to efiect such aheat exchange, and these previously known arrangements wereobjectionable in many instances because of the considerable expense fortheir installation, and in many instances because they did not eilectheat exchangeto a desirable extent. Difliculty was frequentlyexperienced in determining whether or not the heatexchange installationwas war-- porated in the system. That is, where an accumulator, a heatexchanger, and means for controlling the flow of refrigerant weredesired, all of these were incorporatedin the system as separatedevices.

p I with theforegoing in mind, it is an important 2 object of theinstant invention to provide a heat exchange arrangement between ametering tube and the suction line of a. refrigerating system thateffect an extremely high amount of heat exchange. I

Another object of the invention is the provision of a heat exchangearrangement wherein a metering tube is associated for heat exchangepurposes with a part of the suction line of a refrigerating system in anextremely economical manner.

Another object of this invention is the provision of a simple economicalcombination unit embodying both a metering arrangement and a heatexchanging arrangement, which unit may be easily and economicallyinstalled in a refrigerating system with a minimum of labor.

It is also an object of this invention to provide a combination unit forinstallation in a refrigerating system, which unit embodies anaccumulator, a metering tube, and a heat exchanging arrangement ofexceptionally high emciency, the entire unit being installable at oncein the suction line of a refrigerating system.

It is also a feature of this invention to provide a unit forinstallation in a refrigerating system, which embodies a casing forconnection in the suction line of the system, and a metering tube havinga goodly portion thereof disposed within the casing, with the tube soarranged as to provide a minimum amount of restriction to the flow ofrefrigerant while the major portion of the heat exchange takes place,and to provide a higher restriction to the flow of refrigerant while theremainder and considerably lesser portion of the heat exchange operationtakes place.

Still another ob.ect of this invention resides in the provision of aunit for installation in a refrigerating system, which unit includes acasing for connection in the suction line of the system, and a meteringtube having a goodly portion thereof disposed inside the casing, thatportion of the metering tube being of uniform size throughout, and soshaped that the portion through which refrigerant first passes intraveling to the evaporator affords a minimum restriction to the flow ofrefrigerant, while that part of the tube portion in the cas ng throughwhich refrigerant later passes affords a very high re striction.

While some of the more salient features, characteristics and advantagesof the instant invention as mentioned have been above pointed out,others will become apparent from the following trated.

disclosures, taken in conjunction with the accompanying drawing, inwhich:

Figure 1 is a somewhat diagrammatic view of a refrigerating system,showing a unit embodying principles of the instant invention asconnected in operative position in the system, the unit itself beingshown in section;

Figure 2 is an enlarged part sectional part elevational view of the unititself removed from the refrigerating system;

Figure 3 is a vertical sectional view, with parts in elevation, of aunit embody g principles of this invention but of somewhat differentconstruction than that seen in Figures 1 and 2; and

Figure 4 is a transverse vertical sectional view through the right handportion of the metering tube of Figure 3.

As shown in the drawings:

In Figure 1, the first illustrated embodiment of the instant inventionis shown installed in a refrigerating system, diagrammatically illus-This refrigerating system includes a compressor I connected by asuitable fluid line 2 to a condenser 3. The condenser is in turnconnected through a metering tube 4 to an evaporator 5. A portion of themetering tube 4 is incorporated in the unit generally indicated bynumeral 6 which embodies improvements of the instant invention. Thisunit is connected in the suction line of the system so as to form a partof that line, and may be connected directly to the outlet of theevaporator or to an outlet conduit 1 from the evaporator as illustrated,and the opposite end of the unit is connected to the usual suction line8 leading back to the compressor I. If it is desired to employ areservoir in association with the condenser, such may be done, and theinstant invention will not affect the operation of the system includingthe reservoir in any degree.

It is, of course, preferable to have the unit itself disposed as closelyto the evaporator as possible, because the gasified refrigerant leavingthe evaporator is colder in that region. It will be especially notedthat the entire unit may be incorporated in the refrigerating systemwith only one more connection than is required for the system withoutthe unit. That would, of course, be a connection to one end of the unit.And yet, with the provision of the unit illustrated in Figures 1 and 2,the system is provided with an accumulator, a heat exchanger, and ametering device for controlling the flow of refrigerant to theevaporator, as will more fully later appear.

The unit 6 itself embodies a hollow casing 9 larger than the componentparts of the suction line 8 so as to define an interior chamber to thatmay function as an accumulator. At one end thereof the unit is providedwith a fitting H for connection directly to the evaporator outlet or toan outlet conduit 1 as shown in Figure 1, and at the other end the unitis provided with a fitting I! for connection with the suction line 8.Inside the casing 9 is an upwardly inclined pipe l3, one end of which isassociated with the fitting I! in such manner that the pipe formssubstantially an integral part of the suction line. The opposite end ofthe pipe is disposed at a high point, desirably above the fitting H, andthis end of the pipe is freely open. Consequently, if upon the suddenstarting of the compressor I, a slug of liquid refrigerant is withdrawnfrom the evaporator, that slug will pass through the fitting H and fallto the bottom of the chamber ll.

slug will thereupon easily and only the gasified refrigerant will passthrough the pipe I! and the suction line 8 to the compressor, thusavoiding injury to the compressor b way of a slug of liquid reaching it.

A goodly portion of the metering tube 4 is disposed inside the casing I,and it will be understood that where the tube 4 enters and leaves thecasing suitable sealing means are employed. This tube 4, of course,carries liquid refrigerant from the condenser I to the evaporator I. Thetube is designed so that at the same time it carries this liquidrefrigerant, it meters or governs the quantity of liquid refrigerantdelivered into the evaporator.-

Such a tube that is substantially straight or wound into a relativeLvlarge coil requires a considerable length to effect the desired orrequired restriction to refrigerant flow. It is therefore desirable toshape the tube to increase the restriction and thus shorten the lengthnecessary for any particular installation. It is easy to place therequired length of tubing, shaped to increase restriction, inside thecasing 9, and that portion of the tubing inside the casing is obviouslyin heat exchange relationship with the fluid passing through the suctionline I from the evaporator. v

A problem is presented in acquiring the optimum amount of heat exchange.If the tube is highly restricted to refrigerant flow, the pressureobviously must drop, and as the pressure drops the evaporation point ortemperature at which the refrigerant gasifies also drops. Therefore,while it is known that the temperature is dropping in the refrigerantunder pressure, if that pressure is permitted to rapidly drop also acommon point at which the refrigerant gasifles will be reachedprematurely, and thereafter there is no need for any further heatexchange, and the refrigerant is gasifying in the metering tube ratherthan in the evaporator to the detrimental operation of the entiresystem.

The instant invention very capably solves this problem. As seen moreclearly in Figure 2, that portion 44 of the tube 4 inside the casing 9through which the refrigerant first flows is coiled loosely around thepipe [3. It has been found that if this coiling is done so as tomaintain an inside coil diameter of one half inch or more there isnegligible restriction caused by the tube over that of a straight tube.Consequently, the loosely coiled portion I4 affords minimum restrictionand thus the high pressure is maintained. However, while the refrigerantis passing through the part i4 of the tube 4 the temperature of therefrigerant is lowered materially by virtue of the heat exchange action.The remainder of the tube 4 inside the casing 9 is wound in the form ofa tight coil of very small inside diameter, and then this coil is inturn coiled around the pipe I: as indicated at I! thus expanding theturns of the original coil. Coiling a metering tube this fine results ingreatly increasing the restrictive powers of the tube. Pressure, ,ofcourse, will drop rapidly in the portion ii of the tube, but by the timethe pressure is dropping in that portion of the tube, the temperature ofthe refrigerant has been so materially reduced that gasifying of therefrigerant cannot occur. Thus the refrigerant will not vaporize untilit reaches the evaporator, or only to a negligible extent immediatelybefore it reaches the evaporator. At the same time, a great amount ofThe 7 heat exchange has been efiected and the ellia ciency of the entiresystem is thereby materially increased. Aconsiderably greater amount ofheat exchange can be effected with the invention as above described thanhas heretofore been accomplished by previously known means.

In most instances in actual practice, there will be a suflicient length,of tube 4' projecting from the unit 6 to establish connection with theevaporator and the condenser. Thus it can be seen that the entire unitis extremely economical, and veryeasily installed in a refrigeratingsystem, providing an accumulator, a heat exchanger, and a meteringdevice all in the one unit.

In Figures 3 and 4-1 have illustrated another unit Ii, which, embodiesonly a heat exchanger and a metering device. This unit is highlysatisfactory in the event an accumulator is not desired Unit I 6embodies a casing ll which may beconnected to the aforesaid outletconduit 1 from the evaporator at one end and at the other end to thesuction line 8, as above described. Inside the casing H a goodly portionof a metering tube in is disposed. The part of that portion throughwhich the refrigerant first travels is in the form of a, loosely woundcoil Ila of sufficiently great diameter as to provide a minimum amountof restriction. The remainder of that portion of the tube is in the formof a coiled coil i5a, the original coil of which has an extremely smalldiameter so that restriction is very high, and the original coil isitself coiled as above explained to occupy a smaller space and to expandthe turns of the original coil as illustrated at I8 in Figure 4. Theshowing in Figure 4 insofar as actual structure is concerned appliesequally as well to the portion ii of the metering tube seen in Figure 2as it does to portion l5a of. the metering tube seen in Figure 3. Withthe structure of Figure 3, the operation issubstantially the same asabove described except that there is no accumulator action, and the samehigh amount of heat exchange is effected.

Of course, in both embodiments of the invention there will be somerestriction to the flow of refrigerant in the parts It and Ila of thetubes 4 and 4a respectively, but as above stated that restriction is ofvery little amount in comparison with the restriction occurrent in theportions 15 and lid of these tubes. Of course, in the overallinstallation the restriction in the portions l4 and Ma as well as theparts of the respective tubes outside the casings is taken intoconsideration in determining the total amount of restriction desiredbefore the refrigerant reaches the evaporator. This amount ofrestriction, however, is very easily established by virtue of the factthat the portions l4 and Ma of the respective tubes afford substantiallyno more restriction than does a straight length of tube. Since by farthe greater amount of restriction occurs in the portions l5 and [5avariations to fit different systems may readily be made here.

From the foregoing, it is apparent that I have provided a novel andhighly efficient unit for incorporation in a refrigerating system. Theunit may be easily installed, and effects an extremely high degree ofheat exchange as well as providing adequate metering means forcontrolling the flow of refrigerant to an evaporator. If so desired, theunit may be made to function as an accumulator as well. The entire unitis simple in construction, highly durable and economical to manufacture.

It will, of course, be understood that various details of constructionmay be varied through a wide range without departing from the principlesof this invention and it is, therefore, not the purpose to limit thepatent granted hereon otherwise than necessitated bythe scope of theappended claims.

We claim as our invention:

l. A combined metering tube and heat exchanger unit for connection inrefrigerating system. including a housing arranged forconnection nearthe evaporator in the suction side of the system, and a metering tubefor connection in the pressure side of the system, said tube having'arelatively large portion thereof inside said housing, said portion onthe incoming sideaffording relatively low restriction and on the outletside being coiled into a coil of small inside diameter to provide highrestriction to the .flow of refrigerant. Y .1 I y 2. A combined meteringtube and heat exchanger unit for connection in a'refrigerating system,including a housing arranged for connection near the evaporator in thesuction side of the system, and a metering tube for connection in thepressure side of the system, a portion of said tube being within saidhousing, a part of said portion on the incoming side being coiled with asufficiently large diameter to afford little restriction, and the partof said portion on the outlet side being coiled into a coil of smallinside .diameter to provide high restriction to the flow of refrigerant.

3. A combined metering tube and heat exchanger unit for connection in arefrigerating system, including a, housing arranged for connection nearthe evaporator in the suction side of the system, and a metering tube,for connection in the pressure side of the system, a portion of saidtubebeing within said housing, a part of said portion on the incoming sidebeing coiled with a sufliciently large diameter to afford littlerestriction, and the part of said portion on the outlet side beingcoiled and recoiled in a manner to expand the loops of the first coil toprovide high restriction and added surface exposure of the tube.

4. A combined metering tube and heat exchanger unit for connection in arefrigerating system, including a housing arranged for connection nearthe evaporator in the suction side of the system, and a metering tubefor connection in the pressure side of the system, said tube having arelatively large portion inside said housing, said portion on theincoming side afiording relatively low restriction and on the outletside being coiled into a coil of small inside diameter to provide highrestriction to the flow of refrigerant, said metering tube being of thesame size throughout said portion.

5. A combination unit for inclusion in a refrigerating system,comprising a casing, a fitting on each end of said casing connecting thecasing in the suction side of a refrigerating system, an upwardlyinclined open ended pipe in said casing and connected to the fitting onthe compressor side of said casing, and a metering tube for connectionin the high pressure side of a refrigerating system, a portion of saidtube being inside said casing, a part of said portion being looselywound around said pipe in a coil sufficiently large to provide a minimumof restriction to the flow of refrigerant and the remainder of saidportion being wound into a coil of sufficiently small diameter toprovide high restriction.

6. A combination unit for inclusion in a reasses 7 fri ersting system.comprising a casing. a fittin on each end of said casing for connectingthe casing in the suction side of a refrigerating system, an upwardlyinclined open ended pipe in said casing and connected to the fitting onthe compressor side of said casing, and a metering tube for connectionin the high pressure side of a refrigerating system. a portion of saidtube being inside said casing, a part of said portion being looselywound around said pipe in a coil sufficiently large to provide a minimumof restriction to the flow of refrigerant and the remainder of saidportion being wound into a coil of sufficiently small diameter toprovide high restriction, said small diameter coil being coiled aboutsaid pipe in a manner to separate the turns of the small diameter coil.

7. In a combination accumulator, heat exchanging and metering unit for arefrigerating system, a hollow casing for connection in the suction sideof the system, a metering tube for connection in the high pressure sideof the system, and a portion of said tube being inside said casing, apart of said portion being loosely arranged to provide minimumrestriction and of a material length sufficient to cause a substantialdrop in temperature of the refrigerant therein, and a part of saidportion being finely coiled to provide high restriction to the flow ofrefrigerant.

8. In a combination accumulator, heat exchanging and metering unit for arefrigerating system, a hollow casing for connection in the suction sideof the system, a metering tube for connection in the high pressure sideof the system, and a portion of said tube being inside said casing, 'apart of said portion being loosely arranged to provide minimumrestriction and of a material length sumcient to cause a substantialdrop in temperature of the reirigerant therein.andapartofsaidportionbeingfirmlyeoiled to provide high restriction tothe flow of refrigerant, said tube being of the same internal diameterthroughout said portion.

9. In a combination unit for incorporation in the suction side of arefrigerating system, a hollow casing through which refrigerant may passin returning from the evaporator to the com- REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 7 Date 2,181,416 Boles Nov. 28, 19392,188,893 Philipp Jan. 30, 1940 2,393,854 Carpenter Jan. 29, 19462,455,298 Cahenzli Nov. 30, 1948 FOREIGN PATENTS Number Country Date11,177 Great Britain 1896

